[Clinical usefulness of high sensitive PSA with endocrine treatment in the prostate cancer]

Prostate-specific antigen (PSA) is an important tool in the diagnosis of prostatic cancer and also is an essential marker for observing the therapeutic effect and clinical course. Though the conventional limit of PSA measurement was 0.1 ng/ml it recently became possible to determine PSA by means of a 3rd generation high sensitive PSA assay with the detectable sensitivity as highly as 0.003 ng/ml. The clinical utilities of this highly sensitive PSA was examined in this study. METHODS AND SUBJECT: In 51 patients with fresh untreated prostatic cancer diagnosed during the period from November 1996 to March 2001 and for whom endocrine therapy was selected. PSA (Tandem-R) and highly sensitive PSA (DPC Imrise 3rd generation kit) were determined at regular intervals.

According to the nadir for highly sensitive PSA, the subjects were divided into 3 groups, Group, the nadir below 0.01 ng/ml, Group II, the nadir between 0.01 and 0.1 ng/ml and Group III, the nadir of 0.1 ng/ml or more. PSA failure was observed in none of Group I (0/10), 3 out of 19 cases in Group II and 10 out of 21 cases in Group III. Highly sensitive PSA failure was observed 3 out of 11 cases in Group I and 5 out of 19 cases in Group II. Furthermore highly sensitive PSA failure subsequently progressed to PSA failure in 3 cases.

As for the clinical usefulness of highly sensitive PSA in patients with prostatic cancer during endocrine therapy. We propose that; (1) Nadir of highly sensitive PSA might be useful as an index for predicting the prognosis of prostatic cancer and (2) highly sensitive PSA failure could predict a possible recurrence of cancer relatively earlier than PSA failure.